ARDSLEY ADVISORY PARTNERS LP — 13F Holdings & Portfolio

CIK 900529 · latest 13F-HR filed 2026-07-13

ARDSLEY ADVISORY PARTNERS LP manages $960.2M in 13F-reported U.S. long-equity assets across 145 reported positions as of its 2026-06-30 13F-HR filing. Its largest disclosed positions are SNDK (5.90%), AMD (5.63%), SEZL (3.84%). Quarter over quarter (versus its 2026-03-31 filing) the fund opened 58 new positions and exited 45; 42 existing positions rose in reported value and 24 fell.

AUM is the long-equity portion reported on Form 13F-HR. Excludes short positions, cash, foreign holdings, and non-13F assets. For informational purposes only — not investment advice.

AUM

$960.2M

Long-equity book

Holdings

145

Distinct positions

Period

2026-06-30

Filed 2026-07-13

Q/Q Activity

+58 / −45 / ↑42 / ↓24

vs 2026-03-31

Portfolio charts

Latest quarter's book, what changed, and how the portfolio has evolved across filings.

Portfolio map

Q2 26

SNDK6.2% · -40%AMD5.9% · +1062%SEZL4.0% · -28%WULF2.6% · -8%BTSG2.5% · -7%EBAY2.4% · +43%RUN2.3% · +41%VIAV2.0% · -2%P2.0% · new ARM1.8% · +161%SHLS1.8% · -26%AMZN1.8% · -35%UTHR1.8% · -40%TEVA1.7% · -16%GOOG1.7% · +45%PANW1.6% · new TWLO1.5% · +46%PRIM1.5% · new AAPL1.4% · new ZM1.4% · +75%MOD1.3% · -51%ONTO1.3% · new SNX1.3% · new ENPH1.2% · +159%ALGT1.1% · new OKTA1.1% · +13%EQIX1.1% · +26%HUT1.1% · -40%AMLP1.1% · 0%OSCR1.1% · new BE1.0% · +138%CIFR1.0% · -17%NU1.0% · 0%CBRS0.9% · new LITE0.9% · +61%RELY0.9% · new DVN0.9% · new AVGO0.9% · -76%ALK0.8% · -9%GLW0.8% · new FLR0.8% · +73%VRTX0.8% · new VCYT0.8% · 0%SMTC0.8% · -83%JAZZ0.8% · new GSM0.8% · new AKAM0.7% · new VZ0.7% · +19%BOX0.7% · +2%MCHP0.7% · new SLB0.7% · new XIFR0.7% · +10%CAMT0.7% · new MIR0.6% · 0%CRM0.6% · new GMTL0.6% · new WGS0.6% · -25%AAOI0.6% · new ADMA0.5% · +41%CWEN0.5% · 0%

Box size = position value; colour = change in share count vs the prior quarter (green added, red trimmed, blue new). Rows split across managers or share classes are combined. Click a box for the stock.

Sector mix

% of 13F value

Sectors from each company's SIC code; funds and ETFs grouped separately.

Biggest buys and sells

Q1 26 → Q2 26

Estimated from the change in shares held × the quarter-end price, so price moves alone don't count as buying. New and exited positions are included.

13F assets and positions

4 quarters

Total reported 13F value (bars) and number of positions (line) each quarter. Value changes include market moves.

Top positions over time

reported value

The eight largest current positions, valued at each quarter end.

Concentration

top 10 = 31.6%

Cumulative share of the portfolio held in the largest N positions.

Firm Profile & Key People

Assets Under Management

$1.64B

Discretionary

$1.64B

Employees

Accounts

Address

105 ROWAYTON AVE.
NORWALK, CT 06853

Phone

(203) 564-4200

Website

www.ardsley.com

Name	Title / Status	Ownership	Type
ARDSLEY ADVISORY PARTNERS GP LLC Control	GENERAL PARTNER	Less than 5%	Domestic Entity
BALZER, KIRK, DANIEL Control	LIMITED PARTNER	10–25%	Individual
BLOCK, BENJAMIN, IAN Control	LIMITED PARTNER	Less than 5%	Individual
HEMPLEMAN, PHILIP, JAY Control	LIMITED PARTNER	50–75%	Individual
HEMPLEMAN, PHILIP, JAY Control	MANAGING MEMBER	50–75%	Individual
HEMPLEMAN, SPENCER, JAY Control	LIMITED PARTNER	10–25%	Individual
HEMPLEMAN, SPENCER, JAY Control	MANAGING MEMBER	50–75%	Individual
NAPOLI, STEVEN, NICHOLAS Control	LIMITED PARTNER, CHIEF FINANCIAL OFFICER, CHIEF COMPLIANCE OFFICER	Less than 5%	Individual

Quarter-over-quarter changes

Changes in reported position value vs the prior 13F, so price moves count too, not just shares bought or sold.

Top Adds (vs prior quarter)

ADVANCED MICRO DEVICES INC$52.4M +3219.6%
SANDISK CORP$30.0M +112.2%
SEZZLE INC$17.9M +94.3%
ARM HOLDINGS PLC$13.9M +510.5%
EBAY INC.$9.5M +74.1%

Show all 42 →

Top Trims

BROADCOM INC-$19.8M -71.4%
UNITED THERAPEUTICS CORP DEL-$13.4M -45.2%
SEMTECH CORP-$12.6M -63.4%
MODINE MFG CO-$7.7M -39.1%
AMAZON COM INC-$5.6M -25.5%

Show all 24 →

New Positions

Show all 58 →

Exited Positions

Show all 45 →

Loading…

#	Issuer	Symbol	CUSIP	Value	Δ

ARDSLEY ADVISORY PARTNERS LP Holdings (2026-06-30)

Rows tagged Call or Put are options positions, not stock. Per SEC Form 13F-HR, Value shows the notional value of the underlying (shares covered × underlying price), not the option premium. Shares is the number of underlying shares covered (divide by 100 for contract count).

#	Issuer	Symbol	CUSIP	Value	Weight	Shares	Type
1	SANDISK CORP	SNDK	80004C200	$56.7M	5.90%	25,000	SH
2	ADVANCED MICRO DEVICES INC	AMD	007903107	$54.0M	5.63%	93,000	SH
3	SEZZLE INC	SEZL	78435P105	$36.9M	3.84%	215,000	SH
4	TERAWULF INC	WULF	88080T104	$23.7M	2.47%	966,000	SH
5	BRIGHTSPRING HEALTH SVCS INC	BTSG	10950A106	$22.7M	2.36%	325,000	SH
6	EBAY INC.	EBAY	278642103	$22.3M	2.32%	201,000	SH
7	SUNRUN INC	RUN	86771W105	$21.4M	2.23%	1,600,000	SH
8	VIAVI SOLUTIONS INC	VIAV	925550105	$18.6M	1.94%	390,000	SH
9	EVERPURE INC	P	74624M102	$18.3M	1.91%	233,000	SH
10	ARM HOLDINGS PLC	ARM	042068205	$16.6M	1.73%	47,000	SH
11	SHOALS TECHNOLOGIES GROUP IN	SHLS	82489W107	$16.5M	1.72%	1,665,000	SH
12	AMAZON COM INC	AMZN	023135106	$16.4M	1.71%	69,000	SH
13	UNITED THERAPEUTICS CORP DEL	UTHR	91307C102	$16.3M	1.69%	30,000	SH
14	TEVA PHARMACEUTICAL INDS LTD	TEVA	881624209	$15.8M	1.64%	465,000	SH
15	ALPHABET INC	GOOG	02079K107	$15.3M	1.60%	43,500	SH
16	PALO ALTO NETWORKS INC	PANW	697435105	$14.6M	1.52%	43,000	SH
17	TWILIO INC	TWLO	90138F102	$14.2M	1.48%	69,000	SH
18	PRIMORIS SVCS CORP	PRIM	74164F103	$13.4M	1.39%	135,000	SH
19	APPLE INC	AAPL	037833100	$13.0M	1.35%	45,000	SH
20	ZOOM COMMUNICATIONS INC	ZM	98980L101	$12.5M	1.30%	145,000	SH
21	MODINE MFG CO	MOD	607828100	$12.0M	1.25%	45,000	SH
22	ONTO INNOVATION INC	ONTO	683344105	$11.9M	1.24%	31,500	SH
23	TD SYNNEX CORPORATION	SNX	87162W100	$11.6M	1.21%	43,500	SH
24	BROOKDALE SR LIVING INC Call	BKD	112463104	$11.1M	1.16%	690,000	SH
25	ENPHASE ENERGY INC	ENPH	29355A107	$10.8M	1.12%	220,000	SH
26	ALLEGIANT TRAVEL CO	ALGT	01748X102	$10.6M	1.10%	90,000	SH
27	OKTA INC	OKTA	679295105	$10.4M	1.09%	76,500	SH
28	EQUINIX INC	EQIX	29444U700	$10.4M	1.09%	10,000	SH
29	HUT 8 CORP	HUT	44812J104	$10.4M	1.08%	90,000	SH
30	ALPS ETF TR	AMLP	00162Q452	$10.4M	1.08%	200,000	SH
31	OSCAR HEALTH INC	OSCR	687793109	$10.0M	1.04%	350,000	SH
32	BLOOM ENERGY CORP	BE	093712107	$9.4M	0.98%	31,000	SH
33	CIPHER DIGITAL INC	CIFR	17253J106	$9.2M	0.96%	375,000	SH
34	NU HLDGS LTD	NU	G6683N103	$9.0M	0.94%	675,000	SH
35	CEREBRAS SYSTEMS INC	CBRS	15675D103	$8.7M	0.90%	39,000	SH
36	LUMENTUM HLDGS INC	LITE	55024U109	$8.5M	0.89%	10,000	SH
37	REMITLY GLOBAL INC	RELY	75960P104	$8.4M	0.88%	375,000	SH
38	DEVON ENERGY CORP NEW	DVN	25179M103	$8.3M	0.86%	200,000	SH
39	BROADCOM INC	AVGO	11135F101	$7.9M	0.83%	21,000	SH
40	ALASKA AIR GROUP INC	ALK	011659109	$7.8M	0.82%	150,000	SH
41	CORNING INC	GLW	219350105	$7.7M	0.80%	30,000	SH
42	FLUOR CORP	FLR	343412102	$7.5M	0.78%	142,500	SH
43	VERTEX PHARMACEUTICALS INC	VRTX	92532F100	$7.5M	0.78%	15,000	SH
44	VERACYTE INC	VCYT	92337F107	$7.3M	0.76%	125,000	SH
45	SEMTECH CORP	SMTC	816850101	$7.3M	0.76%	45,000	SH
46	JAZZ PHARMACEUTICALS PLC	JAZZ	G50871105	$7.2M	0.75%	30,000	SH
47	FERROGLOBE PLC	GSM	G33856108	$6.9M	0.72%	2,185,000	SH
48	AKAMAI TECHNOLOGIES INC	AKAM	00971T101	$6.6M	0.69%	56,000	SH
49	ORACLE CORP Call	ORCL	68389X105	$6.6M	0.69%	45,000	SH
50	VERIZON COMMUNICATIONS INC	VZ	92343V104	$6.6M	0.68%	155,000	SH

Filing History

Period	Filed	AUM	Holdings	Accession
2026-06-30	2026-07-13	$960.2M	145	0001172661-26-002590
2026-03-31	2026-05-15	$784.4M	151	0001172661-26-002039
2025-12-31	2026-02-17	$911.1M	142	0001172661-26-000864
2025-09-30	2025-11-14	$808.7M	130	0001172661-25-004897

Filer Information

Address

105 ROWAYTON AVE
NORWALK, CT 06853

Phone

(203) 564-4230

Filing Manager

ARDSLEY ADVISORY PARTNERS LP

Norwalk, CT

Signatory

Steven Napoli

Partner